I've seen some on ebay but probably will buy from the link above unless anyone suggests better. Mainly will be using this with Sennheiser HD 650 headphones.

Also after a portable amp to use with my Samsung Galaxy S4 phone. Any decent suggestions with a budget of $200 USD / £130 GBP? Don't want to blow big money on this.
To be used with Earsonics SM64 and Sennheiser IE8 IEM's.
Was looking at the 'FiiO E18 KUNLUN portable Headphone Amplifier & DAC'